I'm trying to calibrate my Natural Point Optitrack IR camera with Open CV 3.0.0 and Visual Studio 2015. I took the camera calibration module that is given when you download OpenC.V 3.0.0 and to calibrate, I used screenshots of an assymetrical circle grid that I made while running the Vector Tracking sample in the Camera SDK.
Here is the images that I have:

ROND3.png (4.1 KiB) Viewed 1889 times

When I run the camera calibration program, I have a memory error ("Exception thrown at ...") but when I try it with the images given by openCV made with RGB cameras, the programm runs without errors so I guess the problem is because of my images.
What do you think? Where do you think this error could come from ? Have y'all tried to calibrate IR cameras with open CV ?